First, it is important to realize that orchids are tough! Think of them as cacti that like more humid conditions. They usually grow slowly, and they also (fortunately) die slowly. I (John) recently bought some orchids from Brazil that were first dryed out (on purpose), removed from their growing medium, fumigated, and shipped through customs before being offered for sale at a West Coast show. I bought them in a shrivelled state at the sale table, and shipped them home by USPS express mail. They were placed directly into my potting medium (below) and treated the same as my other plants, and are now, only two months later, showing new growth and seem to be doing fine. One Laelia with jet lag is even blooming in October thinking it's spring! Orchids are tough, they don't need to be pampered, but they do need certain conditions to do well.
When I visited Costa Rica a few years ago, I discovered that many orchids spend their lives being drenched with rain or fog for many hours each day during the wet season, and also get daily fog or dew and occasional rain during the dry season. Not many of us can provide these conditions, but we don't grow orchids outdoors on trees, instead, we put them in pots. Rainwater, however, is a hint that orchids need clean water, and the chemicals added to our tap water should be avoided, if possible. I use pond water, but I live in an area that has little limestone. Some folks collect rainwater for their plants, some use store-bought distilled water (with nutrients added back...see below), and some use reverse osmosis treated water. NEVER use water that has been passed through a water softener! The salts added during this process can be very harmful.
If you must use tap water, it helps to let it sit for a day so that some of the chlorine can dissipate. I must admit, however, that before I had my greenhouse, I used to put my plants in the shower about once a week with very little negative response (tepid water, cooler than you would like in the morning). But, I would also move the plants outside under a tree that gave dappled light as early in the spring as possible and leave them out as long in the fall as I could, so that they were thoroughly rinsed with rainwater during the summer.
WARNING! I've seen many, many orchids with their roots rotted off from too much water! Now, in the wild, they may get rain every day, but also their roots are exposed to the air and dry out within an hour or so of the rain, fog, or dew event. We grow orchids in pots (usually) in some sort of growing medium, and so we need to let those roots almost dry out in the pot before they are drenched again. How can you tell when it's time? The best way is to stick your finger down into the medium and feel it.
DO NOT let pots sit in water or cover the pot with anything that will restrict airflow around it. If you're growing in the home, you can increase the humidity around the plant be putting the on top of a tray of wet pebbles, but be sure the bottom of the pot stays well above the level of the water. MORE PLANTS ARE KILLED BY OVERWATERING THAN BY BEING TOO DRY, although some plants, like Phaleonopsis, Cymbidiums, Phaius, and other terrestrials, should never completely dry out. All, however, need to dry out a bit, so let them! If you pot in sphagnum, wait until it is just barely soft, if you use a bench mix, as I do, scratch the surface stick a finger in there to make sure it's almost, but not quite dry. If you use bark or coconut fiber, check deep in the pot to make sure that there isn't a wet area. If you use a tree fern or bark mount, or pot in rock, watering can be more frequent. In the case of bark mounts, as much as every day. These latter potting schemes, however, also require good humidity around the plant, and are not usually practical in the home.
I add a soluable 20-14-13 orchid fertilizer at 1/6 the reccomended strength to my plant water, and will use this for three weeks in a row. I then switch to a "bloom booster' 11-35-15 at 1/4 strength for a week, followed by a week with no fertilizer at all in order to wash out any accumulated salts. This way I fertilize almost every time I water. I get these no-urea fertilizers at Lowes Warehouse. Some of my plants are 'heavy feeders', the Zygos, the Phaius, some reed stem Epidendrums and some of the cymbidiums. I will sprinkle a bit of Osmocote on the surface of these pots to add a little extra nitrogen kick.
According to folks who should know, urea cannot be used directly by orchids, and needs to be broken down by soil bacteria. Since most orchids don't grow in soil, fertilizers that have most of their nitrogen in the form of urea should be avoided.
That said, I sometimes still use plain old Miracle-Gro at about 1/4 strength between rain events in the summer, and I used to use it once a month in my windowsill days, but in each of these cases the pots would be rinsed out, either by rain or in the shower, within week or so. Too much fertilizer kills roots and may kill the plant rapidly, too little leads to a slow decline over many years, so start slow and build up if necessary.
Very few orchids can take full sunlight in the summer. Many, however, require 'bright' conditions in order to flower. These include Cattleyas, many Oncidium hybrids and most common department store Dendrobium hybrids (which often were grown in Hawaii). These plants can receive a few hours of morning or late afternoon sun in an east or west facing window in the winter, but need to be placed behind a sheer curtain or outside in dappled shade when the sun gets higher in the sky in the spring. In my windowsill days, I often had plants develop sunburn in the spring when I would move them outdoors before the trees really had enough leaves to shade them. Sunburn makes big, ugly brown or black patches on the leaves, but is seldom lethal. Orchids that like shade, such as Phaleonopsis, Aeranthes, Phaius, and others, should be behind sheer curtains at all times, or placed in a north window. In the summer, they should be placed outside in the shade, with only possibly very early morning sun.
It is said that the leaf color will tell you if the light is right. For Cattleyas, at least, the leaf color should be a medium green. If a yelowish green, there's too much light, if a dark "healthy looking" green, there is too little, and the plant may not bloom. Some plants, however, like Phals and most Angreacum, have dark green leaves when they are healthy. Leaf color is, in fact controlled by fertilizer and temperature as well, so getting the right color involves balancing light with other factors. If you get flowers and your plant grows well, you're doing it right!
My plants grow in an 'intermediate' greenhouse, with a low temperature of about 57 degrees on winter nights and a high of about 95 degrees on hot summer days. In the summer, however, I move almost all of my plants outside into a frame covered with 50% shadecloth, with slightly more cover for shade loving plants. I move them back inside again when night temperatures drop to around 50 degrees. All of my plants seem to do well in these conditions with the exception of Masdevallia coccinea, which gets too hot in the summer, and the Phaleonopsis, which get too cold in the winter. These temperatures are a little cooler than most American rooms, so if you don't have a greenhouse, put the plants close to the window glass in the winter( except the Phals.), and move them outside in the summer.
PESTS AND DISEASE
Cym. 'Golden Elf'
L. purpurata var. flamea
Paph. Maudiae var. coloratum
I won't give a conprehensive treatment of pests and diseases here, but only a few suggestions. Most orchids are more resistant to insect pests than other houseplants, and you should have very little trouble.
SOME POSSIBLE PESTS:
Let me caution that, although orchid plants seem not very sensitive to insecticides, the flower buds seem to be more sensitive, and I have yet to find a remedy that does not deform some flower buds, even the mild remedies given below.
1. For whiteflys, I spray with Neem Oil (mixed 1 tsp./quart with 1/4 tsp. soap added to help it stick and spread). I like Neem because it is less toxic to ME than almost any other efective treatment, and it knocks down whiteflys really well.
2. For scale, I first wipe off any scale I see with a cotton swab wetted with rubbing alcohol, and then treat as above. About once a year, just before I bring the plants into the greenhouse in the fall, I spray with Neem three times at one week intervals, and I very seldom see scale anymore.
3. For aphids, I have to use something a little stronger, like insecticidal soap or even worse. Start with insecticidal soap, then, if necessary, move up to a stronger insecticide, such as Malathion.
I have more trouble with fungal diseases in my wet, Tennessee climate than I do with insects. Most of my problems occur during the wet, warm summer when the plants are outdoors, but a few plants that like warmer conditions than I can give them in my winter greenhouse also develop problems. If you raise orchids in your home, you will probably never see a fungus problem. But....be sure not to crowd plants together to avoid stagnant air around them, and if water collects in the crowns of your plants, dump it out (particularly in Paphs and Phals.)
My first treatment for fungal disease spotting is to use RD-20 (available at most farm or nursery supply stores, or on the web). If the plant doesn't respond, I also use Daconyl (it's not listed for orchids, and there was a bad batch that killed a bunch of orchids in the past, but so far, so good). If these relatively benign remedies don't work, I blitz the plant with a drench of Funginex (available as Rose Pride in Lowe's Warehouse) and a spray of Physan-20. Both of these are pretty potent, and must be used with caution. The Physan-20 will damage flowers, but the worst part is what it can do to you! Be careful with these, reading the lables will give you shivers. As a very last ditch effort, you could cut off the infected part of the plant and soak the rest in RD-20 or Physan before repotting in new medium and drenching with Funginex.
If the plants still don't respond, they're gonners, so just pitch them before they can infect others.
Common orchid viruses are usually transmitted from plant to plant in the sap, Viral diseases are hard to identify, since similar symptoms can be caused by pests or fungus. The presence of the most common viruses can only be confirmed by a lab test (Critter Creek Labs if you have a lot of plants, or you can get "do it yourself" kits for single plants made by Pocket Diagnostic. If you're interested in the details of how these test kits work, visit my "PDTest" page. Since the tests for orchid viruses cost money, it's only worth checking a valuable plant that cannot be easily replaced or that you are considering buying. If you're pretty sure a plant has virus, and hasn't responded to treatment for fungus, you should certainly isolate the plant, and you might consider having it tested or pitching it. Some orchids seem to be able to tolerate a virus with little damage, while others suffer and produce poor blooms (but usually don't die). All carriers are sources of possible infection for your other plants, so keep them isolated. To help keep virus away from your plants, you should:
1. Always use a sterile cutting impliment (such as an unused straight razor blade) to make any cut on your plant, including cutting off flowers. I always follow a cut with a sprinkle of cinnamon on the wound, since the spice is supposed to have anti-viral properties
2. Never pot an orchid in a previously used, unsterilized pot.
3. Play it safe and be sure to thoroughly wash you hands before touching your plants. Always disinfect you workspace before and after you repot or divide a plant.
4. Keep your plants as free of sucking pests as possible.
Don't let this section on pests and diseases scare you. Orchids are tough, and your chances of having serious disease or pest problems are less than they would be if you were growing almost any other houseplant, so don't dispair. Just try to keep your plants in good condition, and they'll fight off just about everything.
In the wild, most orchids we keep in our home grow on trees, sometimes on horizontal branches with ferns, mosses, bromiliads, and other epiphytes, and sometimes by themselves on thinner branches. Many of these orchids can be grown in their natural state by attaching them to branches or bark mounts, but most of us want them in pots, and so we need to consider what to put in the pot with them. This rather long section will discuss a few of the choices, and give positives and negatives for each. Some people succeed with each of these, and some people also fail. The key to success is to realize that in the wild most orchid roots usually can dry out because of good air movement, and we need to allow them to do this in the pot. Different potting media present different challanges, and some media retain water better or allow better better air penetration than others, but whatever you use, be sure to allow the medium to almost dry out before soaking it again. Continuously soggy medium kills most orchids!
I'll begin this section with an old favorite, bark chunks, that I once used, but recently replaced. Then, I'll discuss my current favorite, followed by a series of other choices I sometimes use.
I once thought the mixes made largely of bark chunks were rhe only choice for epiphytic orchids. After all, the plants grow on bark in the wild, right? As of now, however, I have less than one percent of my plants in bark because of the negatives listed below, and I only leave the few plants I have in bark alone because they are doing so well.......rule of thumb: If it ain't broke, don't fix it!
Many people still use bark chunks, but I find the following problems not worth the effort:
1. It's hard to tell how wet the pot is in the middle. As bark ages and begins to decompose, it retains
more and more water, and this happens at the center and bottom of the pot much faster than at the
top. As a result, even though you test the top of inch or so of medium for dampness, it can remain
dangerously soggy in the lower reaches of the pot.
2. Repotting in bark is difficult and it traumatic to the plant!. In order to repot, you need to first remove
the old bark from the roots (to which it tends to stick), and then to pack the new bark chunks around
the roots using a potting stick. This process cannot be done without breaking and bruising a large
number of roots, and this is the reason for reccommending that repotting only be done just before
new roots appear . Of course, this is difficult to predict, and I found that many times I didn't notice
new root growth until it was too late. As a result, I had a tendancy to allow pots to become overgrown
rather than take a chance on hurting the plant.
'SOILLESS' HIGH-POROSITY BENCH MIXES
This is my current favorite. I use Berger BM-6 or a similar high-porosity bench mix (such as ProMix HP or Fafard #1-P) for at least 3/4 of my plants, both terrestials and epiphytes. When I first saw plants growing in this stuff, I couldn't believe that they wouldn't have rotted roots because it looks so much like "potting soil". This isn't soil, however. It contains no clay, and is a mix of ground peat moss, Perlite, and other stuff to give extremely high porosity, balanced pH and good water retention.
1. The moisture content stays uniform throughout the pot, particularly if you use plastic pots, making it easy to tell when it's time to water
2. Repotting is a snap! Simply rinse off the old medium (if it seems to be getting compacted), and
water in new medium around the roots. DO NOT PACK THIS IN THE POT WITH YOUR FINGERS!
The object is to have a light and open mix. I usually cover the bottom of the pot with packing peanuts
so the mix doesn't all run out the drainage holes. Repotting is so easy on the plant that you don't have
to worry about when to repot or damaging roots. I now repot frequently, whenever the plant starts to grow out of the pot. (For more information on repotting, see my "Repotting/Dividing" page).
3. One negative is that these mixes are not available in small quantities at common retail outlets.
I get a bale at a greenhouse supply store (Sonne-Gro) in Knoxville for less than $30, and it lasts me
half a year for my over 300 plants.
4. Another negative is that many plants besides orchids seem to like these mixes, including greenhouse weeds, such as oxalis and ferns. As a result, you have to be vigilant about removing these weeds before they send down deep roots to compete with you orchids.
5. Some people report rapid root rot when the mix starts to break down. I haven't experienced this, perhaps because I'm careful about allowing the mix to dry down a bit before watering and I repot so frequently. Usually, I rinse out and replace the mix once a year or so, which is very quick easy to do, particularly if no dividing is involved.
By sphagnum, I mean long strand New Zeeland sphagnum, of grade AAA or higher. This is a traditional madium used by Japanese growers for some of their native orchids, including the Neofinitia falcata seen at right. I use it for almost all of my Neos., and for my Phal's (the few I have). I had great success with it growing some very small Cynoches seedlings, and have most of my Dendrobium moniliforme plants in it. Still, it has a problem or two.
1. It breaks down in a year or so and needs to be replaced.
This isn't difficult, because it's soft and easily removed from
the roots, although not as easily as BM6.
Neof. falcata 'Gekkeikan'
2. It's easy to overwater, particularly if plants are outdoors and subject to unscheduled watering from
rain. It needs to dry out almost completely before watering again, and in a pot, it may be hard to tell
when this 'almost, but not quite' dry stage occurs. Also, the tightness of packing greatly influences
how much water is retained in the center of the pot, and packing at a consistently proper tightness requires some practice and skill. I like to pack it fairly loosely so it stays airy and water can penetrate to the center of the pack .
BARK OR FERN FIBER MOUNTS
This type of mount most nearly mimics the natural condition of epiphytic orchids, and should be ideal. If you can also effectively mimic the humidity and watering frequency in which the orchid grows, this type of mount should be ideal, however:
1. Orchids on mounts need to be watered frequently during the growing
season, usually daily. With mounts in the home, this means moving the
plant to the source of water, the shower, for example.
2. Because the roots are exposed, the humidity should be kept high
(45% - 70%) around the plant. Although all orchids benefit from this, it is
critical for orchids on mounts, and it is hard to provide in the typical
American home during the winter.
3. The mounts need to hang in an area with the right amount of light, and
can't sit on a windowsill.
(on treefern mount)
In my opinion, this type of mount is only practical in the greenhouse or outside in an appropriate climate. People who grow their orchids in the home should probably avoid plants that need these mounts. I have three plants on mounts which are doing well (including the Dendrobium shown above), but I also have a greenhouse.
I have very little experience with chopped coconut husk, so take what I say with a grain of salt. My only experience comes from examining plants that I bought which were in the medium when I got them.
1. This medium is easier to remove from the roots than bark when repotting, but, of course, not as easy
as a soiless bench mix.
2. The medium holds water better than bark, but it's hard for me to tell when to water because, like bark,
the top drys out when the center is still wet.
3. It needs to be packed in at the right tightness, and the packing can bruise roots, although not as much
4. Chopped coconut husk is not easily available.
Many different potting media work for different people, and the same may fail for others. Success depends on match the medium with watering frequency, repotting frequency and fertilizer application. I find Berger BM6 to be good for most orchids, but I also use long strand New Zeeland sphagnum and have one or two plants in other stuff (bark, mounts, and one in lava rock!) In the final analyses, if your plant seems to be flowering and growing well, stick with it. If not, maybe you need a repot (particularly if it's been over a year or two since it was last done) and maybe a change in medium type. Fortunately, orchids are hard to kill, and no one knows all the answers. SO, EXPERIMENT A LITTLE, AND ENJOY!